Chapter 30 The Nature of the Atom
Jan 19, 2015
Chapter 30
The Nature of
the Atom
30.1 Rutherford Scattering and the Nuclear Atom
In its natural state, an atom is electrically neutral.
30.1 Rutherford Scattering and the Nuclear Atom
A Rutherford scattering experiment.
30.2 Line Spectra
The individual wavelengths emitted by two gases and thecontinuous spectrum of the sun.
30.2 Line Spectra
The Line Spectrum of Hydrogen
Lyman series
Balmer series
Paschen series
,4,3,2 1
1
1122
n
nR
,5,4,3 1
2
1122
n
nR
,6,5,4 1
3
1122
n
nR
30.3 The Bohr Model of the Hydrogen Atom
In the Bohr model, a photon is emitted when the electron dropsfrom a larger, higher-energy orbit to a smaller, lower energyorbit.
hfEE fi
30.3 The Bohr Model of the Hydrogen Atom
THE ENERGIES AND RADII OF THE BOHR ORBITS
r
kZe
r
kZemv
E
2
EPEKE
2
22
21
30.3 The Bohr Model of the Hydrogen Atom
,3,2,1 2
nh
nrmvL nnn
,3,2,1 4
2
22
2
n
Z
n
mke
hrn
,3,2,1 m1029.52
11 nZ
nrn
Radii for Bohr orbits
Angular momentum is quantized.
30.3 The Bohr Model of the Hydrogen Atom
,3,2,1 2
2
2
2
422
n
n
Z
h
emkEn
,3,2,1 J1018.22
218 n
n
ZEn
,3,2,1 eV 6.132
2
nn
ZEn
Bohr energy levels
30.3 The Bohr Model of the Hydrogen Atom
ENERGY LEVEL DIAGRAMS
30.3 The Bohr Model of the Hydrogen Atom
Example 3 The Ionization Energy of Li2+
Li2+ is a lithium atom (Z=3) with only one electron. Obtain the ionizationenergy of Li2+.
eV 1221
3eV 6.13eV 6.13
2
2
2
2
n
ZEn
eV 122energy Ionization
30.3 The Bohr Model of the Hydrogen Atom
THE LINE SPECTRA OF THE HYDROGEN ATOM
fifi
if
nnnn
nnch
emk
,3,2,1,
11
Z 21
222
3
422
30.4 De Broglie’s Explanation of Bohr’s Assumption About Angular Momentum
De Broglie suggested standing particle waves as an explanationfor Bohr’s angular momentum assumption.
,3,2,1 2 nnr